This invention relates to the field of the ignition engines. It concerns an overturn-safe tank cap according to the preamble of claim 1.
Such a tank cap has been already described, for example, by the applicant in a prior utility model application (No. 299 20 579.7).
The tank cap of the prior utility model application has a closing member on the upper side of which two gripping elements are placed which are opposing in a line, spaced from each other, by means of which an operator can twist the closing member into the closing position or can unscrew it out of the closing position. Since such a closing member can easily get stuck in the closing position and is then no longer to loosen or only very hardly, the intermediate space between both gripping elements is configured in such a way that a tool, especially the screw driver part of a combined wrench, such as that which belongs to the accessories of motor-driven hand tools, can be introduced into the intermediate space and can so be used as a lever for applying an additional torque. So as to avoid that this additional torque can also be applied when closing the tank opening and can then cause the overturn of the tank cap, the flanks of the gripping elements which are adjacent to the intermediate space are configured asymmetrically by one-sided bevelled surfaces in such a way that the tool when used as a lever in the closing direction side-slips, while in the opening direction it remains engaged with the closing member.
For comparatively big closing elements, such a solution is appropriate as an overturn safety device because, despite the intermediate space between the gripping elements, the tank cap can be easily operated simply with the hand under normal circumstances and the interruption of the lateral gripping surfaces by the intermediate space and the bevelled surfaces is not very important.
On the other hand, the situation is different when the closing member is considerably smaller. In this case, such a reduction of the gripping surfaces results in that the operator cannot operate the closing member simply with the hand any longer, even under normal circumstances.
Thus, the aim of the invention is to create an overturn-safe tank cap of the type mentioned above which makes possible a safe manipulation simply with the hand, even with reduced size, without having to renounce to the overturn-safe use of a tool (for example, of a combined wrench).
This aim is achieved by the whole characteristics of claim 1. The heart of the invention consists in that the engaging means are configured as an indentation for inserting the tool which penetrates into the closing member from outside transversely to the rotation axis and the shape of the indentation is configured in such a way that the tool, when untwisting, grasps behind a jut and is supported on a supporting surface opposite the jut, while the tool when turning off is unscrewed from the indentation. Due to the configuration of the engaging means as an indentation, the handle on the closing member can practically be configured uninfluenced in such a way that it can be safely operated simply with the hand even when the closing member is small.
Basically, it is conceivable to place the indentation in the basic body of the closing member itself. However, a preferred configuration of the tank cap according to the invention is characterized in that the closing element has on the upper side a longish handle extending transversely over the upper side which is limited on both longitudinal sides respectively by a gripping surface and that the at least one indentation penetrates laterally into the handle from the one of the gripping faces. So, a safe setting possibility for the tool is guaranteed even in case of narrow space conditions.
The access with the tool is still easier if, according to an advantageous further development the at least one indentation is open upwards.
If, according to another preferred embodiment of the tank cap according to the invention, several indentations are placed on the closing member around the rotation axis symmetrically to the axis, the tool can be set more easily in different positions of the closing member because there are different selection possibilities.